{"id":"CVE-2026-93182","revision":"9465b74bc6a34b6491f5007fa3b50dd5","records":[{"revision":"9465b74bc6a34b6491f5007fa3b50dd5","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-93182","aliases":[],"title":"sched/fair: Fix overflow in update_tg_cfs_runnable()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix overflow in update_tg_cfs_runnable()\n\nA divide-by-zero crash is observed when running hackbench:\n\n [14697.488452] CPU: 112 UID: 0 PID: 124791 Comm: hackbench Not tainted 7.1.0-rc2+\n [14697.492627] RIP: 0010:propagate_entity_load_avg+0x35f/0x3e0\n [14697.506799] \n [14697.507411] __dequeue_task+0x2b4/0xc70\n [14697.508677] dequeue_task_fair+0x36/0x370\n [14697.509047] dequeue_task+0x101/0x2f0\n [14697.509426] __schedule+0x1b1/0x1a00\n [14697.510868] anon_pipe_read+0x3da/0x450\n [14697.511400] vfs_read+0x361/0x390\n [14697.512053] __x64_sys_read+0x19/0x30\n\nThe divide-by-zero happens here:\n\n if (scale_load_down(gcfs_rq->load.weight)) {\n load_sum = div_u64(gcfs_rq->avg.load_sum,\n scale_load_down(gcfs_rq->load.weight));\n }\n\ngcfs_rq->load.weight is an insane large value and is truncated\nto the lower 32 bits by div_u64, which happen to be 0.\n\nUsing AI for investigation, the cause is a u32 overflow in\nupdate_tg_cfs_runnable(), and flat pickup became a victim when using\ntg_tasks():\n\n u32 new_sum, divider;\n ...\n new_sum = se->avg.runnable_avg * divider; <-- boom\n\nThe following sequence shows how this triggers the crash:\n\n propagate_entity_load_avg()\n update_tg_cfs_runnable() # u32 overflow corrupts runnable_sum\n\n __update_load_avg_cfs_rq()\n ___update_load_avg() # computes insane runnable_avg\n update_tg_load_avg() # propagates to tg->runnable_avg\n\n update_cfs_group()\n calc_concur_shares()\n tg_tasks() # long-to-int truncation, negative nr\n reweight_entity() # corrupted se->load.weight\n update_load_add() # corrupted cfs_rq->load.weight\n\n propagate_entity_load_avg()\n update_tg_cfs_load()\n div_u64() # divide-by-zero\n\nFix by widening new_sum from u32 to u64 (no need to force tg_tasks()\nto return unsigned long after this fix)","state":0,"publishedAt":"2026-09-17T16:12:09.381+00:00","modifiedAt":"2026-10-19T09:06:55.184+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"kernel/sched/fair.c\"\n ],\n \"versions\": [\n {\n \"version\": \"95246d1ec80b8d19d882cd8eb7ad094e63b41bb8\",\n \"lessThan\": \"39d707097a0820c6e87eff4195f0940e8ff1147e\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"95246d1ec80b8d19d882cd8eb7ad094e63b41bb8\",\n \"lessThan\": \"69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"95246d1ec80b8d19d882cd8eb7ad094e63b41bb8\",\n \"lessThan\": \"7cc237e3bc1733928313d2462b413ae441b0eef3\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"95246d1ec80b8d19d882cd8eb7ad094e63b41bb8\",\n \"lessThan\": \"18fdd0978ec3dda0ff6865cd273e47e022180710\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"95246d1ec80b8d19d882cd8eb7ad094e63b41bb8\",\n \"lessThan\": \"f94e62d21faad5e244d0874598a4d0ebbc0ea405\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"95246d1ec80b8d19d882cd8eb7ad094e63b41bb8\",\n \"lessThan\": \"4f166adb5cb0525d9e32d45729fd8f28c80acbee\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"kernel/sched/fair.c\"\n ],\n \"versions\": [\n {\n \"version\": \"5.17\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"5.17\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.188\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.157\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.110\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.52\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.6\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/39d707097a0820c6e87eff4195f0940e8ff1147e","https://git.kernel.org/stable/c/69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75","https://git.kernel.org/stable/c/7cc237e3bc1733928313d2462b413ae441b0eef3","https://git.kernel.org/stable/c/18fdd0978ec3dda0ff6865cd273e47e022180710","https://git.kernel.org/stable/c/f94e62d21faad5e244d0874598a4d0ebbc0ea405","https://git.kernel.org/stable/c/4f166adb5cb0525d9e32d45729fd8f28c80acbee"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93182","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-93182","identifiers":["CVE-2026-93182"]},"retained":false,"historicalAffected":[]}],"coverage":[]}